The present invention relates to the one-step permanent wave solution, which contains no neutralizing agent. Conventional permanent wave solutions were used in a two-step process. Such two-step permanent wave solutions mainly consist of a reducing solution as a first solution comprising ammonium thioglycolate and an alkaline agent such as ammonia water; and an oxidizing solution as a second solution (so-called “neutralizing agent”) comprising peroxide or sodium bromide.
These two-step permanent wave solutions have the following several problems. First, repeated use of a reducing agent with high alkalinity and a strong oxidizing agent results in de-coloration or damage to the hair as well as irritations to the skin when they are in contact with the skin. Second, ammonium thioglycolate and ammonia water emit repulsive odors, which remain for a long period, even after hair washing, thereby causing discomfort. Third, treatment with a neutralizing agent causes the inconvenience of having to undergo a two-step process, and the solution drips during the permanent waving, causing irritations to skin and damage to clothing.
The reaction mechanism of the conventional two-step permanent wave solution will now be described briefly. Korean Patent No. 134,755 discloses the two-step permanent wave solution. As disclosed in this patent, the R—S—S—R bond of cystine contained in keratin, a constituent of hair, is first broken into R—S—H and H—S—R by a hydrogenation reduction reaction, and then re-bonded by means of an oxidizing agent as illustrated in the following reaction equation in a state where the hair was deformed into curls. Thus, the hair curls are stabilized.

Furthermore, the conventional permanent wave solution is composed of a first solution containing an excess of an alkali compound (e.g., alkali carbonate, caustic alkali, or ammonia water) that has an alkalinity of more than 3.5 as measured in the amount of 0.1N HCl (mL) required for neutralizing 1 mL of the associated alkali. So, applying the first solution onto hair immediately forms a cyanide compound (e.g., potassium cyanide). This cyanide compound functions to break the —S—S— bond of cystine. More specifically, the reaction between cystine (R—S—S—R where R represents keratin) and potassium cyanide (KCN) occurs in two steps as shown in the following reaction equations (i) and (ii):R—S—S—R+KCNR—S—CN+K—S—R  (i)R—S—CN+K—S—RR—S—R·K—S—CN  (ii)
As described above, this reaction produces lanthionine R—S—R and potassium thiocyanide (see C. R. Robbins, “Chemical and Physical Behavior of Human Hair,” Fragrance Journal, p. 56, 1982). Subsequently, as can be seen in the following chemical equation (iii), when using the second solution, thiocyanide (—SCN) is oxidized by alkali bromide, which is an oxidizing agent principally contained in the second solution. Even when the second solution is not used, cyanide (ferric cyanide), which is a byproduct in the waste solution of the permanent wave solution, is oxidized to yield a cyanide compound.—SCN+O2→—CN+SO2  (iii)
As is well known in the art, the cyanide compound reacts with iron contained in hair to form a ferrous hexacyano compound (blue cyanide) or a ferric hexacyano compound (red cyanide).
Besides the above problems, the one-step permanent wave solution, which was recently developed but rarely used, has problems in that the formation of hair curl during the permanent waving is very slow and the curls after the permanent waving readily gets loose by hair washing, thereby deteriorating the product quality.
Accordingly, it is an object of the present invention to solve the problems with the prior art and to provide a one-step permanent wave solution that eliminates the need for using a neutralizing agent during a permanent waving operation, simplifies the permanent wave operation into one step, reduces potential discomfort from contact with the skin, prevents hair damage, makes hair glossy and elastic without odor and provides a pleasant operation condition for the permanent waving.